add webhook for slack notification of PR results (#284)
add webhook for slack notification of PR results (#284)


openwhisk/apigateway,openwhisk/openwhisk-apigateway,alexsong93/openwhisk-apigateway,alexsong93/openwhisk-apigateway,openwhisk/apigateway,openwhisk/openwhisk-apigateway,alexsong93/openwhisk-apigateway,openwhisk/openwhisk-apigateway,openwhisk/apigateway